Brussels’ chief Brexit negotiator said no deal would cause major disruption to the UK economy

He said: “While the 27 member states will find it easier to adjust, as they will still benefit from the single market, the customs union and more than 60 trade deals with their international partners, we believe it is in the best interests of both sides to reach a deal on the UK’s orderly withdrawal from the EU.

“It is the only way to properly protect the rights of EU citizens.”

It comes as Mrs May is urged not to try and stay “half-in, half-out” of the EU customs union and instead pursue a clean break.

Think tank Open Europe said the PM should pull Britain out of the union entirely before striking a new “customs facilitation agreement” as part of a comprehensive free trade deal, similar to those enjoyed by Switzerland and Canada.

Theresa May confirms Article 50 will be triggered during the next two weeks and begin Brexit